Credentialed NIDDK clinical staff members have relevant expertise necessary to support patient care needs of human subjects involved in clinical research conducted by all institutes and centers in the intramural research program. Consultative interactions provided by NIDDK clinicians with expertise in the fields of diabetes, endocrinology, metabolism, gastroenterology, hepatology, nephrology and hematology are required for delivery of specialized medical services to patients throughout the Clinical Research Center at NIH. Beyond patient support services, these consultative interactions lead to collaborative clinical investigations to advance the study of natural history of disease, new approaches to diagnosis and treatment, as well as advancing the understanding of disease pathogenesis and pathophysiology. Clinical services include: 1. Blood Glucose Management Service involves comprehensive management of patients with insulin deficient or insulin resistant diabetes mellitus, including insulin dosing, blood glucose monitoring, and insulin pump management. 2. Consultation services in endocrinology, gastroenterology, hepatology, nephrology, cystic fibrosis and hematology. 3. Gastrointestinal endoscopy, including capsule endoscopy, gut biopsies and therapeutic procedures, such as gut flora transplants and reconstitution. 4. Liver biopsies, portal venous pressure measurements, and liver fibroscanning 5. Renal biopsies, hemodialysis, continuous veno-venous hemofiltration, specialized research renal function tests 6. Biorepository: collection, barcoding, indexing, storing, and retrieving human samples 7. Biostatistical support for developing, monitoring, analyzing clinical research protocols Examples of completed and ongoing collaborative clinical research projects emerging from consultation services and clinical core services include: 1. Endocrine, gastrointestinal, liver and kidney complications of immunotherapy of metastatic melanoma, stem cell transplantation, chemotherapy, radiation, and novel biologic anti-tumor agents and regimens such as CAR-T cell therapies (NCI, NHLBI, NIAID); 2. Gastrointestinal and renal complications of graft versus host disease (NHLBI, NCI, NIAID); 3. Liver and kidney complications of chronic granulomatous disease (NIAID), Hermansky-Pudlak syndrome, methylmalonic acidemia, Erdheim-Chester disease and cystinosis (NHGRI); 4. Natural history and management of kidney and liver complications of sickle cell anemia, including stem cell transplantation (NHLBI); 5. Renal complications of HIV disease and HIV drug therapies (NCI, NIAID); 6. Kidney complications of von Hippel-Lindau disease and hereditary renal cancers (NCI); 7. Membranous nephropathy in patients with non-myeloablative stem cell transplants (NHLBI, NCI); 8. Glomerular disease in ANCA-associated vasculitis (NIAMS); 9. Glomerular endothelial cell injury and thrombotic microangiopathy in stem cell transplants (NHLBI, NCI, NIAID, NIDDK)